Smaller juvenile pets often do well in a 10 or 20 gallon aquarium. As your iguana grows, he must be moved to more comfortable enclosures. These can often be purchased or built by the pet owner. Your veterinarian or pet store may have examples of these larger enclosures to give you an idea of the proper habitat for an adult iguana.
Substrate, or bedding material, should be easy to clean and nontoxic to the iguana. Newspaper, butcher paper, towels, or preferably astroturf is recommended. When using astroturf, buy two pieces and cut them to fit the bottom of the cage. With two pieces, one is placed in the cage and one is kept outside the cage and is always clean. When the turf inside the cage becomes soiled, you'll always have a clean, dry piece to replace it. Clean the soiled turf with ordinary soap and water (avoid harsher products unless your reptile veterinarian approves them), thoroughly rinse it, and hang it to dry to be used at the next cage cleaning.
Alfalfa pellets can also be used for bedding and are often eaten by the iguana, which is acceptable. AVOID sand, gravel, wood shavings, corn cob material, walnut shells, and cat litter, as these are not only difficult to clean but can cause impactions if eaten on purpose or accidentally should the food become covered by these substrates. Cedar wood shavings are toxic to reptiles!
Natural branches are enjoyed by the iguana. Make sure they are secure and won't fall onto the lizard and injure it. Ideally, the branch should slope from the bottom of the enclosure to the top and end near a heat source so the iguana can bask. Rocks (large ones) in the cage also allow for basking. A hiding place is appreciated by all reptiles and should be available. Artificial plants can be arranged to provide a hiding place, as can clay pots, cardboard boxes, and other containers that provide a secure area.
A heat source is necessary for all reptiles, which are cold-blooded and need a range of temperatures to regulate their internal body temperature. Ideally, the cage should be set up so that a heat gradient is established, with one area of the tank warmer than the other end. In this way, the iguana can move around its environment and warm or cool itself as needed. Purchase two thermometers and place one at the cooler end of the cage and one at the warmer end near the heat source. The cooler end of the cage should be approximately 70-75 F, while the warmer end should be 90-100 F. An inexpensive way to do this is to supply a focal heat source using a 100-watt incandescent bulb with a reflector hood, although pet stores sell other types of heat lamps. Your heat source should be placed OUTSIDE and above one end of the cage, which should be covered by a screen top to prevent the iguana from escaping or burning itself on the bulb. At night, heat isn't necessary as long as the temperature remains at 65-70 F.
Heating pads can also be used for warmth; speak with your veterinarian to learn the correct way to use them if you choose this form of heating.
"Hot Rocks" or "Sizzle Rocks" are dangerous, ineffective, and should be avoided!